I grant that without lots of economic storage/sinks, you'd hit the cieling on renewables faster if you have a share of nuclear in the system as well. So if your goal is to increase renewables to their highest penetration before hitting their cieling before needing storage, then you'd want to back off of nuclear. But if your goal is to get to the lowest carbon power system as possible before needing storage, then I doubt that's the best way to go.
Simple math here but I think this gets at the gist of it: if your system is say 20% nuclear, then you'd hit the renewables cieling roughly when their energy share = their capacity factor x (100% - nuclear's share). So for solar at 10% CF, you'd hit the cieling at 10% x (100% - 20%) = about 8% of the energy mix from solar instead of 10% if you had no nuclear in the system. For wind at 33% CF, you'd hit the cieling at 33% x (100% - 20%) = about 26% of the energy mix from wind instead of about 33% if you had no nuclear in the system.
So yes, you lose a few percentage points of renewables share if you have 20% nuclear in your system versus if you don't. But if carbon is your priority, it makes no sense to give up that 20% from zero-carbon nuclear in order to get 2% more solar or 7% more wind!
So again: if you want an ultra low-carbon energy system with high penetrations of solar or wind, you need massive amounts of economic storage and sinks and DR. And if you have those, nuclear and renewables seem to work just fine together. And if nuclear and renewables aren't mutally exclusive, the lowest CO2 for the least money may very well be a hybrid system.